Backed into a corner after severe criticism of their leader Arvind Kejriwal's vitriolic attack on Prime Minister Narendra Modi on Twitter after raids by the Central Bureau of Investigation (CBI), the Aam Aadmi Party (AAP) on Thursday sought to strike back at the ruling Bharatiya Janata Party (BJP) by demanding that Union Minister Arun Jaitley resign to ensure fair probe by agencies in an alleged graft case.

"The main objective of the CBI raid at the Delhi Secretariat and taking control of Anti-Corruption Branch was to prevent the alleged graft in DDCA during Arun Jaitley's tenure from coming to light," AAP leaders alleged during a press conference in the national capital.

Letter below is a proof that some one in BJP wants to fix Mr Jaitley ? Who is that ? Is order from the top ? pic.twitter.com/coPFO146Pm

"A free and fair probe cannot be done as long as Jaitley remains in the post," AAP's Sanjay Singh said. Cabinet minister Kapil Mishra also dared the PM "to remove Jaitley till he came out clean" as Kejriwal had publicly sacked one of his ministers who had allegedly sought bribes.

"This scam was about siphoning off money by creating fake companies between 1999 and 2013 and one year after that. This went on for 15 years," AAP leader Kumar Vishwas told reporters. "When we tried to raise this with the Anti-Corruption Branch, it was taken away from us. The Chief Minister's office was raided. His daily diary was taken up," NDTV quoted him as saying.

The party alleged that money was taken out of DDCA through fake firms.

BJP leader Nupur Sharma countered the AAP attack by saying that the way Kejriwal jumped to the defence of his principal secretary, whose office was raided by the CBI in an alleged corruption case, it indicated that he "is hiding something".

The Congress had also joined the Aam Aadmi Party in demanding Jaitley's resignation for a fair and impartial inquiry into the DDCA irregularities. Kejriwal had called Modi a coward and a psychopath on Twitter, leading to a massive backlash. Twitter users said the CM's language tarnished the dignity of his office.